Bacon has been proven time and again to make everything—sandwiches, salads, doughnuts, even butter crackers—better. And the rise of passionate bacon lovers, there has been a corresponding increase in consumers' access to many different types of bacon at supermarkets, butcher shops, and specialty stores. But if you've ever wondered what the difference is between slab bacon and back bacon, or between pancetta and guanciale, you're not alone.

I called Joseph Cordray, an extension meat specialist in the Department of Animal Science at Iowa State University, to talk about how this most popular of foodstuffs gets to market, what shelf-stable bacon is about, and how to store bacon at home (if for some bizarre reason you don’t just eat it all up).

What is bacon?

Bacon is cured and smoked pork belly cut crosswise into strips. If it comes from anywhere on the pig other than the belly (shoutout to the late Sizzlean), the label has to specify where.

Canadian bacon is cut from the loin, above the belly, so it’s leaner.

British back bacon is a happy medium between Canadian and American bacon—it’s cut from the loin but with some of the fat from the belly attached.

Pancetta, often called Italian bacon, is cured but not smoked and shaped into a roll. Grocery stores often sell pancetta in thin, round slices or already diced, but butcher and specialty shops usually slice it to order.

Guanciale comes from the pig’s cheek or jowl. Like pancetta, it’s cured but not usually smoked. It can be hard to find outside of a good butcher shop or Italian or specialty market.

Slab bacon, which you can usually find at butcher shops, isn’t sliced. It comes in a large slab so you can slice it however thickly or thinly you want.

“Center-cut” bacon is from the center portion of the belly, which has the most consistent ratio of fat to lean, says Cordray. For this reason, you’ll pay a little more for it.

You’ll also pay more for certified organic bacon. The “natural” label, however, is an unregulated term; you can ignore it.

The other bacon

Bacon made from another animal, such as turkey, can be labeled bacon (purists, bite your tongue), but the packaging has to clearly state exactly what the bacon is made of, according to USDA regulations.

Three ways to cure bacon

Most supermarket bacon is conventionally cured. It’s a quick process that involves injecting pork belly with a brine containing sodium nitrite, the crucial ingredient that gives bacon its pink hue and helps preserve it, Cordray says. The meat is then “tumbled” under a vacuum to distribute the brine.

Uncured bacon goes through the same process. The difference is the brine, which instead of sodium nitrite contains ingredients that are natural sources of nitrates, such as celery powder. These nitrates convert to nitrite once they interact with bacteria in the meat. Uncured bacon must, by law, be labeled with the phrase, “No nitrates or nitrites added except those naturally occurring."

Dry-curing, the third method, is old school. The pork is rubbed with a dry mix of salt, sugar, and sodium nitrite and left to cure for up to 10 days in a cooler. It’s a lengthier, lower-yield process, which is why dry-cured bacon is pricier, Cordray says. You’ll find it more at specialty markets and butcher shops.

Smoke and chill

After curing, bacon is heated to 128 degrees and smoked using hardwood (hickory, applewood, even pecanwood), liquid smoke, or a combination of both, Cordray says. Then it’s chilled down to around 26 degrees, sliced and packaged.

Mass-produced bacon is put into a press before slicing, which is why each slice comes out identical in shape and weight.

Bacon, ready to eat

Pre-cooked bacon is shelf-stable like jerky; enough moisture has been driven out of it during cooking that bad bacteria can’t grow. Because of the processing involved, it is more expensive per pound than fresh bacon.

Even though there’s no need to refrigerate pre-cooked bacon until after it’s opened, you’ll find it in the cooler case next to the regular bacon. This is mostly to ease the consumers' psyches. “We want to see bacon that’s refrigerated,” Cordray says.

The best ways to store bacon

An unopened package of bacon will keep in the fridge for up to two weeks after you buy it. But once you break the seal, cook it within seven days, keeping whatever bacon you don’t use wrapped, sealed in a container or airtight bag, and refrigerated.

Or freeze it. One good method: roll individual slices and pack them into freezer bags. Frozen bacon, which is how it’s typically sold at farmers’ markets, will keep indefinitely, but for the best results, the USDA recommends using it within two months.

You can even freeze cooked bacon, something Cordray swears by. He’ll cook an entire pound and store the slices in a freezer bag. “When we want some, we just zap it in the microwave,” he says.